出典(authority):フリー百科事典『ウィキペディア(Wikipedia)』「2015/11/13 17:43:11」(JST)
Breastfeeding or nursing is feeding of babies and young children with milk from a woman's breast.[1] It is recommended to begin breastfeeding within the first hour of life and after that allow it as the baby wishes.[2][3] During the first few weeks of life babies may nurse eight to twelve times a day (every two to three hours). The duration of a feeding is usually ten to fifteen minutes on each breast.[4] The frequency of feeding decreases as the child gets older.[5] Some mothers pump milk so that it can be used later when their child is being cared for by others.[1] Breastfeeding benefits both mother and baby.[3][6] Infant formula does not have many of the benefits.[3]
It is estimated that greater than a million babies could be saved globally per year through greater breastfeeding. Breastfeeding decreases the risk of respiratory tract infections and diarrhea.[3] This is true both in developing and developed countries.[2] Other benefits include a lower risk of asthma, food allergies, celiac disease, type 1 diabetes, and leukemia.[3] Breastfeeding may also improve cognitive development and decrease the risk of obesity in adulthood.[2] Some mothers may feel considerable pressure to breastfeed, but children who are not breastfed grow up normally – without significant harm to their future health.[7]
Benefits of breastfeeding for the mother include less blood loss following delivery, better uterus shrinkage, weight loss, and less postpartum depression. It also increases the time before menstruation and fertility returns, known as lactational amenorrhea. Long term benefits may include a decreased risk of breast cancer, cardiovascular disease, and rheumatoid arthritis.[3] Breastfeeding is less expensive for the family than infant formula.[8][9]
Health groups, such as World Health Organization (WHO), support six months of just breastfeeding.[2][10] This means that no other foods or drinks other than vitamin D are typically given.[11] Continued partial breastfeeding until at least a year of age is then recommended.[3] Globally about 38% of infants are just breastfeed during their first six months of life.[2] In the United States about 75% of women begin breastfeeding and about 43% breastfeed until six months.[3] Medical conditions that do not allow breastfeeding are uncommon.[3] During breastfeeding drugs, and certain medications are not recommended.[12]
The endocrine system drives milk production during pregnancy and the first few days after the birth. From the twenty-fourth week of pregnancy (the second and third trimesters), a woman's body produces hormones that stimulate the growth of the breast's milk duct system. Progesterone influences the growth in size of alveoli and lobes; high levels of progesterone, estrogen, prolactin and other hormones inhibit lactation before birth; hormone levels drop after birth, triggering milk production.[13] After birth, the hormone oxytocin contracts the smooth muscle layer of cells surrounding the alveoli to squeeze milk into the duct system. Oxytocin is also necessary for the milk ejection reflex, or let-down to occur. Let down occurs in response to the baby's suckling, though it also may be a conditioned response, e.g. to the cry of the baby. Lactation can also be induced by a combination of physical and psychological stimulation, by drugs or by a combination of these methods.[14][15]
Not all of breast milk's properties are understood, but its nutrient content is relatively consistent. Breast milk is made from nutrients in the mother's bloodstream and bodily stores. Breast milk has an optimal balance of fat, sugar, water, and protein that is needed for a baby's growth and development.[17] Breastfeeding triggers biochemical reactions which allows for the enzymes, hormones, growth factors and immunologic substances to effectively defend against infectious diseases for the infant. The breastmilk also has long-chain polyunsaturated fatty acids which help with normal retinal and neural development.[18] Because breastfeeding requires an average of 500 calories a day, it helps the mother lose weight after giving birth.[19]
The composition of breast milk changes depending on how long the baby nurses at each session, as well as on the child's age.[20] The first type, produced during the first days after childbirth, is called colostrum. Breast milk is produced soon after birth. Early in a nursing session, the breasts produce foremilk, a thinner milk containing many proteins and vitamins. If the baby keeps nursing, then hindmilk is produced. Hindmilk has a creamier color and texture because it contains more fat.[21]
Milk quality may be compromised by smoking, caffeinated drinks, marijuana, methamphetamine, heroin and methadone.[22][unreliable medical source?] However, the American Academy of Pediatrics (AAP) states that "tobacco smoking by mothers is not a contraindication to breastfeeding."[23] In addition, AAP states that while breastfeeding mothers "should avoid the use of alcoholic beverages", an "occasional celebratory single, small alcoholic drink is acceptable, but breastfeeding should be avoided for 2 hours after the drink."[23] A 2014 review found that "even in a theoretical case of binge drinking, the children would not be subjected to clinically relevant amounts of alcohol [through breastmilk]", and would have no adverse effects on children as long as drinking is "occasional".[24]
Books and videos advise mothers about breastfeeding. Lactation consultants in hospitals or private practice, and volunteer organizations of breastfeeding mothers such as La Leche League International also provide advice and support.
Breastfeeding can begin immediately after birth. The baby is placed on the mother and feeding starts as soon as the baby shows interest.
According to some authorities, increasing evidence suggests that early skin-to-skin contact (also called kangaroo care) between mother and baby stimulates breastfeeding behavior in the baby.[25] Newborns who are immediately placed on their mother’s skin have a natural instinct to latch on to the breast and start nursing, typically within one hour of birth. Immediate skin-to-skin contact may provide a form of imprinting that makes subsequent feeding significantly easier. WHO reported that in addition to more successful breastfeeding and bonding, immediate skin-to-skin contact reduces crying and warms the baby.
According to studies cited by UNICEF, babies naturally follow a process which leads to a first breastfeed. Initially after birth the baby cries with its first breaths. Shortly after, it relaxes and makes small movements of the arms, shoulders and head. The baby crawls towards the breast and begins to feed. After feeding, it is normal for a baby to remain latched to the breast while resting. This is sometimes mistaken for lack of appetite. Absent interruptions, all babies follow this process. Rushing or interrupting the process, such as removing the baby to weigh him/her, may complicate subsequent feeding.[26] Activities such as weighing, measuring, bathing, needle-sticks, and eye prophylaxis wait until after the first feeding."[23]
Newborn babies typically express demand for feeding every 1 to 3 hours (8-12 times in 24 hours) for the first two to four weeks.[27]
According to La Leche League International, "Experienced breastfeeding mothers learn that the sucking patterns and needs of babies vary. While some infants' sucking needs are met primarily during feedings, other babies may need additional sucking at the breast soon after a feeding even though they are not really hungry. Babies may also nurse when they are lonely, frightened or in pain....Comforting and meeting sucking needs at the breast is nature's original design. Pacifiers (dummies, soothers) are a substitute for the mother when she cannot be available. Other reasons to pacify a baby primarily at the breast include superior oral-facial development, prolonged lactational amenorrhea, avoidance of nipple confusion, and stimulation of an adequate milk supply to ensure higher rates of breastfeeding success."[28]
During the newborn period, most breastfeeding sessions take from 20 to 45 minutes.[27] After one breast is empty, the mother may offer the other breast.
Most US states now have laws that allow a mother to breastfeed her baby anywhere. In hospitals, rooming-in care permits the baby to stay with the mother and simplifies the process. Some commercial establishments provide breastfeeding rooms, although laws generally specify that mothers may breastfeed anywhere, without requiring a special area. Breastfeeding in public remains controversial in many developed countries.
In 2014, newly elected Pope Francis drew world-wide commentary when he encouraged mothers to breastfeed babies in church. During a papal baptism, he said that mothers "should not stand on ceremony" if their children were hungry. "If they are hungry, mothers, feed them, without thinking twice," he said, smiling. "Because they are the most important people here."[29]
Correct positioning and technique for latching on are necessary to prevent nipple soreness and allow the baby to obtain enough milk.[30]
Babies can successfully latch on to the breast from multiple positions. Each baby may prefer a particular position. The "football" hold places the baby's legs next to the mother's side with the baby facing the mother. Using the "cradle" or "cross-body" hold, the mother supports the baby's head in the crook of her arm. The "cross-over" hold is similar to the cradle hold, except that the mother supports the baby's head with the opposite hand. The mother may choose a reclining position on her back or side with the baby laying next to her.[31]
The "rooting reflex" is the baby's natural tendency to turn towards the breast with the mouth open wide; mothers sometimes make use of this by gently stroking the baby's cheek or lips with their nipple to induce the baby to move into position for a breastfeeding session, then quickly moving the baby onto the breast while its mouth is wide open.[32] To prevent nipple soreness and allow the baby to get enough milk, a large part of the breast and areola need to enter the baby's mouth.[33][34] Failure to latch on is one of the main reasons for ineffective feeding and can lead to infant health concerns.
Weaning is the process of replacing breast milk with other food. The infant is fully weaned after the replacement is complete. Most mammals stop producing the enzyme lactase at the end of weaning, and become lactose intolerant. Figures vary, but worldwide, humans lose about 75 to 95 percent of birth lactase levels by early childhood, and lactase continues to decline with age. However, the prevalence varies widely among ethnic backgrounds. Estimates range from 2 to 5 percent in those with Northern European ancestry to nearly 100 percent in adult Asians and American Indians. Africans and Ashkenazi Jews have prevalences of 60 to 80 percent, while Latinos have a prevalence of 50 to 80 percent.[35][36]
Psychological factors affect the weaning process for both mother and infant, as issues of closeness and separation are very prominent.[37]
In the past bromocriptine was in some countries frequently used to reduce the common engorgement experienced during weaning. This is now done only in exceptional cases due to frequent side effects and slight benefits.[38] Other medications such as cabergoline, lisuride or birth control pills may occasionally be used to suppress lactation.
Exclusive breastfeeding is defined as "an infant's consumption of human milk with no supplementation of any type (no water, no juice, no nonhuman milk and no foods) except for vitamins, minerals and medications."[23] Exclusive breastfeeding has reduced infant deaths in developing countries by reducing diarrhea and infectious diseases. It also reduced HIV transmission from mother to child, compared to mixed feeding.[39][40][41][42]
Measuring how many calories a breastfed baby consumes is complex, although babies normally attempt to meet their own requirements.[43] Babies that fail to eat enough may exhibit symptoms of failure to thrive.
La Leche League says that mothers' most often asked question is, "How can I tell if my baby is getting enough milk?" They advise that for the first few days, while the baby is receiving mostly colostrum, one or two wet diapers per day is normal. Once the mother starts producing milk, usually on the third or fourth day, the baby should have 6-8 wet cloth diapers (5-6 wet disposable diapers) per day. In addition, most young babies have at least two to five bowel movements every 24 hours for the first several months.[44]
La Leache League offers the following additional signs that indicate a baby is receiving enough milk:
Predominant or mixed breastfeeding means feeding breast milk along with infant formula, baby food and even water, depending on the child's age.[45]
A mother can "express" (produce) her milk for storage and later use. Expression occurs with massage or a breast pump. It can be stored in freezer storage bags, containers made specifically for breastmilk, a supplemental nursing system, or a bottle ready for use. Using someone other than the mother/wet nurse to deliver the bottle maintains the baby's association of nursing with the mother/wet nurse and bottle feeding with other people.
Breast milk may be kept at room temperature for up to six hours, refrigerated for up to eight days or frozen for six to twelve months.[46] Research suggests that the antioxidant activity in expressed breast milk decreases over time, but remains at higher levels than in infant formula.[47]
Mothers express milk for multiple reasons. Expressing breast milk can maintain a mother's milk supply when she and her child are apart. A sick baby who is unable to nurse can take expressed milk through a nasogastric tube. Some babies are unable or unwilling to nurse. Expressed milk is the feeding method of choice for premature babies.[48] Viral disease transmission can be prevented by expressing breast milk and subjecting it to Holder pasteurisation.[49] Some women donate expressed breast milk (EBM) to others, either directly or through a milk bank. This allows mothers who cannot breastfeed to give their baby the benefits of breast milk.
Babies feed differently with artificial nipples than from a breast. With the breast, the infant's tongue massages the milk out rather than sucking, and the nipple does not go as far into the mouth. Drinking from a bottle takes less effort and the milk may come more rapidly, potentially causing the baby to lose desire for the breast. This is called nursing strike, nipple strike or nipple confusion. To avoid this, expressed milk can be given by means such as spoons or cups.[45]
"Exclusively expressing", "exclusively pumping", and "EPing" are terms for a mother who exclusively feeds her baby expressed milk. With good pumping habits, particularly in the first 12 weeks while establishing the milk supply, it is possible to express enough milk to feed the baby indefinitely. With the improvements in breast pumps, many women exclusively feed expressed milk, expressing milk at work. Women can leave their infants in the care of others while traveling, while maintaining a supply of breast milk.[50]
Wet nursing was common throughout history. It remains popular in some developing nations, including those in Africa, for more than one woman to breastfeed a child. Shared breastfeeding is a risk factor for HIV infection in infants.[51] A woman who is engaged to breastfeed another's baby is known as a wet nurse. Shared nursing can sometimes provoke negative reactions in the Anglosphere.[52][53]
Feeding two children at the same time who are not twins or multiples is called tandem nursing. Appetite and feeding habits of each baby may differ, so they may feed at the same or different times, which may involve feeding them simultaneously, one on each breast.
Breastfeeding triplets or larger broods is a challenge given babies' varying appetites. Breasts can respond to the demand and produce larger milk quantities; mothers have breastfed triplets successfully.[54][55][56]
Tandem nursing occurs when a woman gives birth while breastfeeding an older child. During the late stages of pregnancy, the milk changes to colostrum. While some children continue to breastfeed even with this change, others may wean. Breastfeeding a child while pregnant with another may be considered a form of tandem feeding for the nursing mother, as she provides nutrition for two.[57]
Induced lactation, also called adoptive lactation, is the process of starting breastfeeding in a woman who did not give birth.[58] This usually requires the adoptive mother to take hormones and other drugs to stimulate breast development and promote milk production. In some cultures, breastfeeding an adoptive child creates milk kinship that built community bonds across class and other hierarchal bonds.[58]
Re-lactation is the process of restarting breastfeeding.[58] In developing countries, mothers may restart breastfeeding after a weaning as part of an oral rehydration treatment for diarrhea. In developed countries, re-lactation is common after early medical problems are resolved, or because a mother changes her mind about breastfeeding.
Re-lactation is most easily accomplished with a newborn or with a baby that was previously breastfeeding; if the baby was initially bottle-fed, the baby may refuse to suckle. If the mother has recently stopped breastfeeding, she is more likely to be able to re-establish her milk supply, and more likely to have an adequate supply. Although some women successfully re-lactate after months-long interruptions, success is higher for shorter interruptions.[58]
Techniques to promote lactation use frequent attempts to breastfeed, extensive skin-to-skin contact with the baby, and frequent, long pumping sessions.[58] Suckling may be encouraged with a tube filled with infant formula, so that the baby associates suckling at the breast with food. A dropper or syringe without the needle may be used to place milk onto the breast while the baby suckles. The mother should allow the infant to suckle at least ten times during 24 hours, and more times if he or she is interested. These times can include every two hours, whenever the baby seems interested, longer at each breast, and when the baby is sleepy when he or she might suckle more readily. In keeping with increasing contact between mother and child, including increasing skin-to-skin contact, grandmothers should pull back and help in other ways. Later on, grandmothers can again provide more direct care for the infant.[59]
These techniques require the mother's commitment over a period of weeks or months. However, even when lactation is established, the supply may not be large enough to breastfeed exclusively. A supportive social environment improves the likelihood of success.[58] As the mother's milk production increases, other feeding can decrease. Parents and other family members should watch the baby's weight gain and urine output to assess nutritional adequacy.[59]
A WHO manual for physicians and senior health workers citing a 1992 source states: "If a baby has been breastfeeding sometimes, the breastmilk supply increases in a few days. If a baby has stopped breastfeeding, it may take 1-2 weeks or more before much breastmilk comes."[59]
Extended breastfeeding means breastfeeding after the age of 12 or 24 months, depending on the source. In Western countries such as the United States, Canada, and Great Britain, extended breastfeeding is relatively uncommon. In 2011, 49% of infants were breastfed for six months.[60] For example, in the United States overall, only 22.4% of babies are breastfed for 12 months. In India, mothers commonly breastfeed for 2 to 3 years.[61]
Breastfeeding decreases the risk of a number of diseases in both mothers and babies.[62]
Early breastfeeding is associated with fewer nighttime feeding problems.[63] Early skin-to-skin contact between mother and baby improves breastfeeding outcomes, increases cardio-respiratory stability and decreases infant crying.[64] Reviews from 2007 found numerous benefits. Breastfeeding aids general health, growth and development in the infant. Infants who are not breastfed are at mildly increased risk of developing acute and chronic diseases, including lower respiratory infection, ear infections, bacteremia, bacterial meningitis, botulism, urinary tract infection and necrotizing enterocolitis.[65][66] Breastfeeding may protect against sudden infant death syndrome, insulin-dependent diabetes mellitus, Crohn's disease, ulcerative colitis, lymphoma, allergic diseases, digestive diseases and may enhance cognitive development.[23]
The average breastfed baby doubles its birth weight in 5 to 6 months. By one year, a typical breastfed baby weighs about 2½ times its birth weight. At one year, breastfed babies tend to be leaner than formula-fed babies, which improves long-run health.[67]
The Davis Area Research on Lactation, Infant Nutrition and Growth (DARLING) study reported that breastfed and formula-fed groups had similar weight gain during the first 3 months, but the breastfed babies began to drop below the median beginning at 6 to 8 months and were significantly lower weight than the formula-fed group between 6 and 18 months. Length gain and head circumference values were similar between groups, suggesting that the breastfed babies were leaner.[68]
Breast milk contains several anti-infective factors such as bile salt stimulated lipase (protecting against amoebic infections) and lactoferrin (which binds to iron and inhibits the growth of intestinal bacteria).[69][70]
Infants who are exclusively breastfed for the first six months are less likely to die of gastrointestinal infections than infants who switched from exclusive to partial breastfeeding at three to four months.[71]
During breastfeeding, approximately 0.25–0.5 grams per day of secretory IgA antibodies pass to the baby via milk.[72][73] This is one of the important features of colostrum.[74] The main target for these antibodies are probably microorganisms in the baby's intestine. The rest of the body displays some uptake of IgA,[75] but this amount is relatively small.[76]
Maternal vaccinations while breastfeeding is safe for almost all vaccines. Additionally, the mother's immunity obtained by vaccination against tetanus, diphtheria, whooping cough and influenza can protect the baby from these diseases, and breastfeeding can reduce fever rate after infant immunization. However, smallpox and yellow fever vaccines increase the risk of infants developing vaccinia and encephalitis.[77][78]
Babies who are not breastfed are almost six times more likely to die by the age of one month than those who receive at least some breastmilk.[79]
Infants exclusively breastfed have less chance of developing diabetes mellitus type 1 than those with a shorter duration of breastfeeding.[66] Breastfed infants appear to have a lower likelihood of developing diabetes mellitus type 2 later in life.[65][66][80]
The protective effect of breastfeeding against obesity is consistent, though small, across many studies.[65][66][81] A 2013 longitudinal study reported less obesity at ages two and four years among infants who were breastfed for at least four months.[82]
In children who are at risk for developing allergic diseases (defined as at least one parent or sibling having atopy), atopic syndrome can be prevented or delayed through 4-month exclusive breastfeeding, though these benefits may not persist.[83]
Breastfeeding may reduce the risk of necrotizing enterocolitis (NEC).[66]
Breastfeeding by a mother who eats gluten-containing foods reduces the risk of celiac disease.[84]
About 19% of leukemia cases may be prevented by breastfeeding for six months or longer.[85]
Breastfeeding may decrease the risk of cardiovascular disease in later life, as indicated by lower cholesterol and C-reactive protein levels in breastfed adult women.[65] Breastfed infants have somewhat lower blood pressure later in life, but it is unclear how much practical benefit this provides.[65][66]
A 1998 study suggested that breastfed babies have a better chance of good dental health than formula-fed infants because of the developmental effects of breastfeeding on the oral cavity and airway. It was thought that with fewer malocclusions, breastfed children may have a reduced need for orthodontic intervention. The report suggested that children with a well rounded, "U-shaped" dental arch, which is found more commonly in breastfed children, may have fewer problems with snoring and sleep apnea in later life.[86]
It is unclear whether breastfeeding improves intelligence later in life. Several studies found no relationship after controlling for confounding factors like maternal intelligence (smarter mothers were more likely to breastfeed their babies).[66][87] However, other studies concluded that breastfeeding was associated with increased cognitive development in childhood, although the cause may be increased mother–child interaction rather than nutrition.[65]
Breastfeeding aids maternal physical and emotional health. Breastfeeding and depression in the mother are associated.[88] Mothers who successfully breastfeed are less likely to develop postpartum depression.[89]
Hormones released during breastfeeding help to strengthen the maternal bond.[17] Teaching partners how to manage common difficulties is associated with higher breastfeeding rates.[90] Support for a breastfeeding mother can strengthen familial bonds and help build a paternal bond.[17][91]
Exclusive breastfeeding usually delays the return of fertility through lactational amenorrhea, although it does not provide reliable birth control. Breastfeeding may delay the return to fertility for some women by suppressing ovulation. Mothers may not ovulate, or have regular periods, during the entire lactation period. The non-ovulating period varies by individual. This has been used as natural contraception, with greater than 98% effectiveness during the first six months after birth if specific nursing behaviors are followed.[92]
Breastfeeding releases beneficial hormones into the mother's body.[73] Oxytocin and prolactin hormones relax the mother and increase her nurturing response.[93] This hormone release can help to enable sleep. Breastfeeding soon after birth increases the mother's oxytocin levels, making her uterus contract more quickly and reducing bleeding. Pitocin, a synthetic hormone used to make the uterus contract during and after labour, is structurally modelled on oxytocin. Syntocinon, another synthetic oxytocic, is commonly used in Australia and the UK rather than Pitocin.[94]
It is unclear whether breastfeeding causes mothers to lose weight after giving birth.[66]
For breastfeeding women, long-term health benefits include reduced risk of breast cancer, ovarian cancer, and endometrial cancer.[23][66]
The majority of mothers intend to breastfeed at birth. Many factors can disrupt this intent.
Work is the most common cited reason for not breastfeeding.[95] In 2012 Save the Children examined maternity leave laws, ranking 36 industrialized countries according to their support for breastfeeding. Norway ranked first, while the United States came in last.[96] Maternity leave in the US varies widely, including by state, despite the Family Medical Leave Act (FMLA), which guarantees most mothers up to 12 weeks unpaid leave. The majority of US mothers resume work earlier.
Infants that are otherwise healthy uniformly benefit from breastfeeding. "No known disadvantages" stem from breastfeeding.[100] However, extra precautions should be taken or breastfeeding be avoided in circumstances including certain infectious diseases, or use of certain medications.[101] In some cases it may not be feasible for the mother to continue breastfeeding.[102]
A number of hospital-employed procedures have been found to interfere with breastfeeding, including routine mother/baby separation, delayed initiation, vigorous routine suctioning, medications and mode of delivery.[103]
Pain caused from mis-positioning the baby on the breast or a tongue-tie in the infant can cause pain in the mother and discourage her. These problems are generally easy to correct (by re-positioning or clipping the tongue-tie).[104]
Breast surgery, including breast implants or breast reduction surgery, reduces the chances that a woman will have sufficient milk to breastfeed.[105] Women whose pregnancies are unintended are less likely to breast feed their babies.[106]
The central concern about breastfeeding in the presence of maternal HIV is risks of the child becoming infected. Factors such as the viral load in the mother’s milk complicate breastfeeding recommendations for HIV-positive mothers.[107]
In mothers who are treated with antiretroviral drugs the risk of HIV transmission with breastfeeding is 1 to 2%.[2] Therefore of breastfeeding is still recommended in areas of the world with death from infectious diseases is common.[2] Infant formula should only be given if this can be safely done.[2]
WHO recommends that national authorities in each country decide which infant feeding practice should be promoted by their maternal and child health services to best avoid HIV transmission from mother to child.[108] Other maternal infection of concern include active untreated tuberculosis or human T-lymphotropic virus.
Breastfeeding mothers should inform their healthcare provider about all of the medications they are taking, including herbal products. Nursing mothers can safely take many over-the-counter drugs and prescription drugs and receive immunizations, but certain drugs, including painkillers and psychiatric drugs, may pose a risk.
The U.S. National Library of Medicine publishes "LactMed", an up-to-date online database of information on drugs and lactation. Geared to both healthcare practitioners and nursing mothers, LactMed contains over 450 drug records with information such as potential drug effects and alternate drugs to consider.[78][109]
Some pollutants in the mother's food and drink are passed to the baby through breast milk, including mercury (found in some carnivorous fish),[110] caffeine,[111] and bisphenol A.[112][113]
Race, ethnicity and socioeconomic status affect choice and duration in the United States. A 2011 study found that on average, US women who breastfed had higher levels of education, were older and were more likely to be white.[114]
The reasons for the persistently lower rates of breastfeeding among African American mothers are not well understood, but employment may play a role. They tend to return to work sooner than white mothers, and are more likely to work in unsupportive environments.
Although return to work is associated with early discontinuation, a supportive work environment may encourage mothers to continue.
Low-income mothers are more likely to have unintended pregnancies.[114] Mothers whose pregnancies are unintended are less likely to breastfeed.[106]
Negative perception of breastfeeding in social settings has led some women to feel discomfort when breastfeeding in public.[115] Public breastfeeding is forbidden in some places, not addressed by law in others, and a granted legal right in others. Even given a legal right, some mothers are reluctant to breastfeed,[116][117] while others may object to the practice.[118]
Some public places and workplaces, rooms for mothers to nurse in private have been designated.
The invention of formula was hypothesized as a way for western culture to adapt to negative perceptions of breastfeeding.[119] The breast pump offered a way for mothers to supply breast milk with most of formula feeding's convenience and without enduring possible disapproval of nursing.[120]
Western society tends to perceive breasts in sexual terms instead of for their biological purpose.[121] This view led many to object to breastfeeding because of the implicit association between infant feeding and sex.[122] Many women feel embarrassed to breast-feed in public.[116] These negative cultural connotations may reduce breastfeeding duration.[116][123][124]
Maternal guilt and shame is often affected by how a mother feeds her infant. These feelings result from her inability to behave according to her definition of a "good mother". These feelings occur in both bottle- and breast- feeding mothers, although for different reasons. Bottle feeding mothers may feel that they should be breastfeeding.[125] Conversely, breastfeeding mothers may feel forced to feed in uncomfortable circumstances. Some may see breastfeeding as, “indecent, disgusting, animalistic, sexual, and even possibly a perverse act."[121] Advocates use "nurse-ins" to show support for breastfeeding in public.[115] Some advocates emphasize providing women with education on breastfeeding's benefits as well as problem-solving skills.[125]
Globally about 38% of babies are just breastfeed during their first six months of life.[2] In the United States as of 2008, 75% of women started breastfeeding, 44% breastfeed for six months, and 23% breastfeed for twelve months.[127]
Breastfeeding rates in different parts of China vary considerably.[128]
In the Egyptian, Greek and Roman empires, women usually fed only their own children. However, breastfeeding began to be seen as something too common to be done by royalty, and wet nurses were employed to breastfeed the children of the royal families. This extended over time, particularly in western Europe, where noble women often made use of wet nurses. Lower-class women breastfed their infants and used a wet nurse only if they were unable to feed their own infant. Attempts were made in 15th-century Europe to use cow or goat milk, but these attempts were not successful. In the 18th century, flour or cereal mixed with broth were introduced as substitutes for breastfeeding, but this was also unsuccessful.
During the early 1900s, breastfeeding started to be viewed negatively by Western societies, especially Canada and the US. These societies considered it a low class and uncultured practice.[129] This coincided with the appearance of improved infant formulas in the mid 19th century and its increased use, which accelerated after World War II. From the 1960s onwards, breastfeeding experienced a revival which continued into the 2000s, though negative attitudes towards the practice were still entrenched up to 1990s.[129]
Breastfeeding is cheaper than alternatives, but is not free of cost. The mother generally must eat more food than otherwise. In the US, the extra money spent on food (about US$13 each week) is usually about half as much money as the cost of infant formula.[130]
Breastfeeding represents an opportunity cost, as the mother must spend hours each day breastfeeding instead of other activities, such as paid work or home production (such as growing food). In general, the higher the mother's earning power, the less likely she is to save money by breastfeeding.[131]
Breastfeeding reduces health care costs and the cost of caring for sick babies. Parents of breastfed babies are less likely to miss work and lose income because their babies are sick.[130]
Support for breastfeeding is universal among major health and children's organizations. WHO states, "Breast milk is the ideal food for the healthy growth and development of infants; breastfeeding is also an integral part of the reproductive process with important implications for the health of mothers.".[132] WHO's guidelines recommend "continue[d] frequent, on-demand breastfeeding until two years of age or beyond."[133][134]
The European Commission,[135][136] the US Centers for Disease Control and Prevention[137] (CDC), UNICEF, AAP,[3] Save The Children and the UK National Health Service[138] (NHS), Australian Department of Health,[139] Health Canada, Canadian Paediatric Society, Dietitians of Canada, and Breastfeeding Committee for Canada,[140] recommend exclusive breastfeeding for six months following birth and continued nursing for an additional eighteen months or more.[2][141] Save the Children states, "Six months of exclusive breastfeeding increases a child’s chance of survival at least six-fold."[142]
Authorities generally advise avoiding bottle feeding until the baby is 4–6 weeks old and is nursing successfully.[143]
International board certified lactation consultants (IBCLCs) are health care professionals certified in lactation management. They work with mothers to solve breastfeeding problems and educate families and health professionals. Exclusive and partial breastfeeding are more common among mothers who gave birth in IBCLC-equipped hospitals.[144]
Advocates oppose marketing of infant formula, especially in developing countries. They are concerned that mothers who use formula will stop breastfeeding and become dependent upon substitutes that are unaffordable or less safe.[145][146] Through efforts including the Nestlé boycott, they have advocated for bans on free samples of infant formula and for the adoption of pro-breastfeeding codes such as the International Code of Marketing of Breast-milk Substitutes by the World Health Assembly in 1981 and the Innocenti Declaration by WHO and UNICEF policy-makers in August 1990.[145]
Breastfeeding research currently focuses on diverse aspects such as prevalence, HIV transmission, pharmacology, costs, benefits, immunology, contraindications, and comparisons to synthetic breast milk substitutes.[147][148]
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リンク元 | 「母乳栄養」「母乳で育てること」「breast feeding」 |
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